The 421 class are a class of diesel locomotives built by Clyde Engineering Granville for the New South Wales Government Railways in 1965/66. These mainline locomotives were a follow on from the 42 class. The 421s retained the classic bulldog nose as with the other Clyde built GM and S locomotives at one end but featured a flat-cab at the other end. In this respect they are unique amongst bulldog nose locomotives in the world.
